SOLUTION: A right angled triangle with hypotenuse 20cm. A square 6cm placed in the right angle of the triangle. The hypothenuse touches the top right corner of the square. What is length o

Algebra ->  Triangles -> SOLUTION: A right angled triangle with hypotenuse 20cm. A square 6cm placed in the right angle of the triangle. The hypothenuse touches the top right corner of the square. What is length o      Log On


   



Question 1074446: A right angled triangle with hypotenuse 20cm. A square 6cm placed in the right angle of the triangle. The hypothenuse touches the top right corner of the square.
What is length of other two sides?
I started usi g similar triangles and called base (x+6) and height (y+6) getting
y=36/x. Then use Pythagoras. But can't simplify the complicated algebra I get after that.
Can anyone help?

Found 2 solutions by Alan3354, Fombitz:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
I did the same, got
x^4 + 12x^3 - 328x^2 + 432x + 1296 = 0
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I used a graph to find x.
x =~ 3.0405155
--> the x side is 6 plus that, or that can be the y side, they're interchangeable.
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I'm looking for another method, don't have one yet.

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
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By Pythagoras,
%28x%2B6%29%5E2%2B%28y%2B6%29%5E2=20%5E2
By similar triangles,
y%2F6=%28y%2B6%29%2F%28x%2B6%29
So,
6%28y%2B6%29=y%28x%2B6%29
%28x%2B6%29=%286%28y%2B6%29%29%2Fy
%28x%2B6%29%5E2=%2836%28y%2B6%29%5E2%29%2Fy%5E2
Substituting,
%2836%28y%2B6%29%5E2%29%2Fy%5E2%2B%28y%2B6%29%5E2=400
36%28y%2B6%29%5E2%2By%5E2%28y%2B6%29%5E2=400y%5E2
36%28y%5E2%2B12y%2B36%29%2B%28y%5E4%2B12y%5E3%2B36y%5E2%29=400y%5E2
%2836y%5E2%2B432y%2B1296%29%2B%28y%5E4%2B12y%5E3%2B36y%5E2%29=400y%5E2
y%5E4%2B12y%5E3%2B72y%5E2%2B432y%2B1296=400y%5E2
y%5E4%2B12y%5E3-328y%5E2%2B432y%2B1296=0
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Graphing finds two positive solutions,
y=3.04 and y=11.84
with corresponding x values,
%28x%2B6%29=%286%28y%2B6%29%29%2Fy
x=11.84 and x=3.04
So then the lengths of the other sides are,
x%2B6=17.84cm
y%2B6=9.04cm